Dynamic Connectivity in Disk Graphs

Let S ⊆ R 2 be a set of n sites in the plane, so that every site s ∈ S has an associated radius r s > 0 . Let D ( S ) be the disk intersection graph defined by S, i.e., the graph with vertex set S and an edge between two distinct sites s , t ∈ S if and only if the disks with centers s, t and radii r s , r t intersect. Our goal is to design data structures that maintain the connectivity structure of D ( S ) as sites are inserted and/or deleted in S. First, we consider unit disk graphs, i.e., we fix r s = 1 , for all sites s ∈ S . For this case, we describe a data structure that has O ( log 2 n ) amortized update time and O ( log n / log log n ) query time. Second, we look at disk graphs with bounded radius ratio Ψ , i.e., for all s ∈ S , we have 1 ≤ r s ≤ Ψ , for a parameter Ψ that is known in advance. Here, we not only investigate the fully dynamic case, but also the incremental and the decremental scenario, where only insertions or only deletions of sites are allowed. In the fully dynamic case, we achieve amortized expected update time O ( Ψ log 4 n ) and query time O ( log n / log log n ) . This improves the currently best update time by a factor of Ψ . In the incremental case, we achieve logarithmic dependency on Ψ , with a data structure that has O ( α ( n ) ) amortized query time and O ( log Ψ log 4 n ) amortized expected update time, where α ( n ) denotes the inverse Ackermann function. For the decremental setting, we first develop an efficient decremental disk revealing data structure: given two sets R and B of disks in the plane, we can delete disks from B, and upon each deletion, we receive a list of all disks in R that no longer intersect the union of B. Using this data structure, we get decremental data structures with a query time of O ( log n / log log n ) that supports deletions in O ( n log Ψ log 4 n ) overall expected time for disk graphs with bounded radius ratio Ψ and O ( n log 5 n ) overall expected time for disk graphs with arbitrary radii, assuming that the deletion sequence is oblivious of the internal random choices of the data structures.

Long Term Outcomes of Radiation (RT)-Monotherapy vs. Combined RT + Endocrine Therapy (RT+ET) in Low-Risk Early-Stage Breast Cancer Patients 70 Years or Older after Breast-Conserving Surgery (BCS)

PURPOSE/OBJECTIVE(S)

Combined Radiation and Endocrine Therapy (RT+ET) and ET Monotherapy are acceptable adjuvant strategies based on randomized trial data. Less is known about RT Monotherapy as a form of treatment de-escalation. Radiation delivery has become safer and more convenient. This study compares long-term outcomes in patients who opted for RT-Monotherapy versus combined RT+ET.

MATERIALS/METHODS

This retrospective study included female patients from Swedish Cancer Institute breast cancer registry (Seattle, WA), aged ≥70 years with estrogen receptor-positive (ER+)/human epidermal growth factor receptor 2-negative (HER2-) T1N0 breast cancer treated with BCS between 1995 and 2015. Patients with positive surgical margins, multifocality, histologic grade 3 and LVI were excluded. Patients were classified into 4 groups: (1) RT+ET (reference); (2) RT Monotherapy; (3) ET Monotherapy; and (4) neither RT nor ET (NT). Choice of therapy was determined by the treating physician and the patient. The primary endpoints were local recurrence (LR), distant metastasis (DM), disease specific survival (DSS), overall survival (OS), and second breast cancer events (SBCEs). Competing risk models were used to estimate cumulative incidence at varying lengths of follow-up and sub distribution hazard ratios (HR) between treatment groups. Significance was set at P ≤ .05.

RESULTS

We analyzed 496 patients with a median age of 76 years and median follow-up of 9.6 years. 62% (N = 307) of patients received combined RT+ET, 30% (N = 148) RT Monotherapy, 4% (N = 20) ET alone and 4% (N = 21) no therapy, NT group. Only the RT monotherapy and combined RT+ET groups were large enough for a meaningful statistical analysis. RT monotherapy conferred non-inferior disease control compared to combined RT+ET. Recurrence events were extremely low. Incidence of SBCEs was not significantly different between treatments.

CONCLUSION

For this favorable patient population, RT monotherapy was associated with equivalent long-term outcomes compared to combined RT+ET therapy. Recurrence rates stayed extremely low with long-term FU. RT monotherapy may be a reasonable de-escalation option for this older low risk patient population. Further prospective trials are needed to help refine treatment strategies that allow for more choices in treatment de-escalation.

Insight as a dual-perspective construct: Convergence between patients' and professional evaluators' perspective on baseline level of insight and on changes in insight

Insight gained by patients during treatment has been theorized to be a central mechanism of change in psychotherapy, but empirical studies examining the association between patients' insight and psychopathological symptoms have produced mixed results. The present study addresses these inconsistencies by investigating convergence between the perspectives of patient and professional evaluator on insight and disentangling two potentially distinct components of insight: pretreatment individual differences and changes in insight during treatment. A sample of 393 patients receiving psychodynamic psychotherapy completed pre- and posttreatment measures on symptoms and insight. Professional evaluators evaluated patients' insight based on clinical interviews pre- and posttreatment. Polynomial regression and response surface analyses were used to examine congruence. The results indicate that when there was agreement between the patient and the evaluator on insight, both baseline level of insight and the changes in insight during treatment were found to be related to symptomatic change, although showing different patterns of association. Lower baseline levels of insight were significantly associated with greater symptomatic improvement than were higher levels of insight. At the same time, greater increase in insight during treatment was moderately significantly associated with greater reduction in symptoms, as long as the changes in insight were not minimal. The findings underscore the importance of assessing the congruence between patients' and professional observers' perspectives on patient insight and the potentially distinct roles of between-patients baseline differences and within-patient changes in insight during treatment. (PsycInfo Database Record (c) 2021 APA, all rights reserved).

Deep learning analysis provides accurate COVID-19 diagnosis on chest computed tomography

INTRODUCTION

Computed Tomography is an essential diagnostic tool in the management of COVID-19. Considering the large amount of examinations in high case-load scenarios, an automated tool could facilitate and save critical time in the diagnosis and risk stratification of the disease.

METHODS

A novel deep learning derived machine learning (ML) classifier was developed using a simplified programming approach and an open source dataset consisting of 6868 chest CT images from 418 patients which was split into training and validation subsets. The diagnostic performance was then evaluated and compared to experienced radiologists on an independent testing dataset. Diagnostic performance metrics were calculated using Receiver Operating Characteristics (ROC) analysis. Operating points with high positive (>10) and low negative (<0.01) likelihood ratios to stratify the risk of COVID-19 being present were identified and validated.

RESULTS

The model achieved an overall accuracy of 0.956 (AUC) on an independent testing dataset of 90 patients. Both rule-in and rule out thresholds were identified and tested. At the rule-in operating point, sensitivity and specificity were 84.4 % and 93.3 % and did not differ from both radiologists (p > 0.05). At the rule-out threshold, sensitivity (100 %) and specificity (60 %) differed significantly from the radiologists (p < 0.05). Likelihood ratios and a Fagan nomogram provide prevalence independent test performance estimates.

CONCLUSION

Accurate diagnosis of COVID-19 using a basic deep learning approach is feasible using open-source CT image data. In addition, the machine learning classifier provided validated rule-in and rule-out criteria could be used to stratify the risk of COVID-19 being present.

Abstract AP30: PHASE IB/II WITH EXPANSION OF PATIENTS AT THE MTD STUDY OF OLAPARIB PLUS WEEKLY (METRONOMIC) CARBOPLATIN AND PACLITAXEL IN RELAPSED OVARIAN CANCER PATIENTS

BACKGROUND: We established the olaparib tablet maximum tolerated dose (MTD) at 150 mg bid, dose limiting toxicities (DLT's) and response to therapy or carboplatin, paclitaxel and olaparib tablet given simultaneously, reported at ASCO 2014. This abstract will include data from both the phase 1b and the phase 2 expansion.

METHODS: A total of 54 subjects were evaluated in this trial, 14 in phase 1b and 40 in phase 2. Eligibility required measurable disease, adequate organ function and ECOG performance status of ~ 2. Subjects had to have failed first line platinum containing chemotherapy. BRCA testing was conducted as available. Subjects received the metronomic therapy of paclitaxel 60mg/m2 IV and carboplatin AUC 2 IV weekly, 3 weeks out of 4, and olaparib tablets at 150 mg bid administered orally for 3 consecutive days (D1-D3) every week for each cycle. Subjects were assessed for toxicity and response according to the protocol. Subjects that reached a confirmed complete remission were transitioned to olaparib tablets only, 300 mg bid until disease progression.

RESULTS: Median age was 58 and median number of prior regimens was 4. There have been no deaths due to the study regimen. One patient had grade 4 neutropenia and an allergic reaction to carboplatin. The common grade 3/4 toxicities were caused by the chemotherapy (neutropenia. anemia and thrombocytopenia). Two patients had mild GI toxicities. One patient had a skin rash. There was no evidence of cardiac, hepatic, or pulmonary toxicities in any of these patients. 25% of subjects had a complete remission (CR), 31% had PR, 23% had SD and 21% had

PD. Of the 13 CRs, 4 were BRCA negative. PFS median for BRCA positive subjects is 12.6 months vs 4.8 months for BRCA negative subjects. OS median for BRCA positive subjects is 24 months vs 16 months for BRCA negative subjects. All of the CR's are alive.

CONCLUSION: Olaparib tablet can be safely administered simultaneously with a weekly regimen of carboplatin and paclitaxel in heavily pretreated ovarian cancer patients. Olaparib appears to be highly effective in BRCA positive subjects. This is the first successful combination of olaparib tablets with carboplatin and paclitaxel that has been well tolerated.

Citation Format: Rivkin SE, Moon J, Iriarte D, Sloan H, Wiseman C, Klee M, Ference K, Drescher C, Veljovich D, Bondurant A, Peters W, Jiang P, Goodman G, Park M, Fer M, Shah C, Johnston E, Kaplan H, Wahl T, Ellis E. PHASE IB/II WITH EXPANSION OF PATIENTS AT THE MTD STUDY OF OLAPARIB PLUS WEEKLY (METRONOMIC) CARBOPLATIN AND PACLITAXEL IN RELAPSED OVARIAN CANCER PATIENTS [abstract]. In: Proceedings of the 11th Biennial Ovarian Cancer Research Symposium; Sep 12-13, 2016; Seattle, WA. Philadelphia (PA): AACR; Clin Cancer Res 2017;23(11 Suppl):Abstract nr AP30.

The AND-OR Game

We consider a simple simultaneous first price auction for two identical items in a complete information setting. Our goal is to analyze this setting for a simple, yet highly interesting, AND-OR game, where one agent is single minded and the other is unit demand. We find a mixed equilibrium of this game and show that every other equilibrium admits the same expected allocation and payments. In addition, we study the equilibrium, highlighting the change in revenue and social welfare as a function of the players’ valuations.

Tension Band Wiring of Unstable Transverse Fractures of the Proximal and Middle Phalanges of the Hand

Twenty-three isolated, unstable and closed transverse middle and proximal phalangeal shaft fractures in 23 patients were treated by tension band wiring. The tension band was applied with two transverse Kirschner wires that did not cross the fracture line. All of the fractures united and achieved satisfactory functional outcomes. No patient required either physiotherapy or tenolysis or capsulotomy surgery.

Abstract P6-02-07: Persistence of patient detected breast cancer in the mammography screening era: 1990-2013

Background: It is estimated from most current National Health Interview Study data that 72% of women age 50-74 have had a screening mammogram in the past 2 years which is significantly less than the Healthy People 2020 goal of 81%. It is not known to what extent breast cancer (BC) is patient diagnosed vs. mammography diagnosed in the community.

Methods: We examined method of breast cancer diagnosis among a large institutional cohort of age 50-74 first primary breast cancer patients with no history of prior cancer identified between 1990 and 2013 (n=5736). Patients were all biopsy proven BC with diagnostic data abstracted from the charts and recorded in our breast cancer specific registry database. Chart recorded detection method was by patient presenting with a personally detected breast symptom (PtD) (n=1729), physician discovered physical findings (PhysD) (n=260) or by routine mammography in absence of physical complaints or findings (MammD) (n=3747). It is not known if patients participated in screening programs. Patients with unknown or other BC diagnosis method were excluded (n=91). BC staging was converted to AJCC 7 to remove inconsistency over time. Pearson chi square was used for bivariate comparisons and logistic regression for identification of characteristics associated with patient detection.

Results: Rate of patient detection of all stage BC decreased over time from 43% in 1990 to 27% in 2013 (chi square = 119.45, p&lt;.001) (n= 5736). Rate of detection of invasive BC (excluding stage 0) decreased over time from 45% to 33% (chi square = 87.14, p &lt;.001) (n=4690). Stage shift to lower stage disease occurred over time with the decrease in PtD BC and increase in MamD BC. Stage 0 BC increased from 4% to 24% (20%), stage I BC decreased from 57% to 44% (13%) and stage III BC decreased from 15% to 7% (8%) (chi square = 232.51, p&lt;.001). Constant over time, stage II, III and IV breast cancer were most often patient detected (stage II 49%, stage III 70%, stage IV 81%, chi square = 1333.03, p&lt;.001). In a logistic regression model adjusted for diagnosis year using PtD vs MamD BC as the outcome, non-white race, younger age (50-59) and all invasive breast cancer stages (not 0/DCIS) were significantly related to an increased risk of BC being diagnosed by the patient [non-white RR =1.32, 95% CI = 1.11, 1.59; age 50-59 RR = 1.43, 95% CI = 1.22, 1.69; stage I RR = 3.55, 95% CI = 2.73, 4.63; stage II RR = 15.42, 95% CI = 11.79, 20.17; Stage III RR = 38.61, 95% CI = 28.20, 52.87; Stage IV RR = 133.72, 95% CI = 61.89, 288.92].

Conclusions: Our results indicate improvement in mammography screening may be obtained by reaching out to women of non-white race and younger screening recommended age groups. Higher stage disease requiring extensive treatment for cure or diagnosed as incurable metastatic disease is significantly associated with patient detection. The number of higher stage patient detected cancers indicates a portion of the population may not be screened and are at risk for serious disease in an era when mammography screening is widely available.

Citation Format: Malmgren J, Atwood M, Kaplan H. Persistence of patient detected breast cancer in the mammography screening era: 1990-2013. [abstract]. In: Proceedings of the Thirty-Eighth Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2015 Dec 8-12; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2016;76(4 Suppl):Abstract nr P6-02-07.

Trade-Offs between female food acquisition and child care among hiwi and ache foragers

Even though female food acquisition is an area of considerable interest in hunter-gatherer research, the ecological determinants of women's economic decisions in these populations are still poorly understood. The literature on female foraging behavior indicates that there is considerable variation within and across foraging societies in the amount of time that women spend foraging and in the amount and types of food that they acquire. It is possible that this heterogeneity reflects variation in the trade-offs between time spent in food acquisition and child care activities that women face in different groups of hunter-gatherers. In this paper we discuss the fitness trade-offs between food acquisition and child care that Hiwi and Ache women foragers might face. Multiple regression analyses show that in both populations the daily food acquisition of a woman's spouse is negatively related to female foraging effort. In addition, nursing mothers spend less time foraging and acquire less food than do nonnursing women. As the number of dependents that a woman has increases, however, women also increase foraging time and the amount of food they acquire. Some interesting exceptions to these general trends are as follows: (a) differences in foraging effort between nursing and nonnursing women are less pronounced when fruits and roots are in season than in other seasons of the year; (b) foraging return rates decrease for Ache women as their numbers of dependents increase; and (c) among Ache women, the positive effect of number of dependents on foraging behavior is less pronounced when fruits are in season than at other times of the year. Lastly, in the Hiwi sample we found that postreproductive women work considerably harder than women of reproductive age in the root season but not in other seasons of the year. We discuss how ecological variation in constraints, the number of health insults to children that Hiwi and Ache mothers can avoid, and the fitness benefits they can gain from spending time in food acquisition and child care might account for differences and similarities in the foraging behaviors of subgroups of Hiwi and Ache mothers across different seasons of the year. Valid tests of the explanations we propose will require considerable effort to measure the relationship between maternal food acquisition, child care, and adverse health outcomes in offspring.

Early Involvement of Immune/Inflammatory Response Genes in Retinal Degeneration in DBA/2J Mice

Purpose

The DBA/2J (D2) mouse carries mutations in two of its genes, Tyrp1 and Gpnmb. These alterations result in the development of an immune response in the iris, leading to iris atrophy and pigment dispersion. The development of elevated intraocular pressure (IOP) in this model of glaucoma is considered to be a significant factor leading to the death of retinal ganglion cells (RGCs). Changes in gene expression in the retina have already been correlated with the appearance of elevated IOP in the D2 mouse. The purpose of the present study was to determine if any changes in gene expression occur prior to the development of IOP.

Methods

The IOP was measured monthly using a rebound tonometer in D2 and age-matched C57/BL6 (B6) mice (normal controls). D2 animals with normal IOP at 2 and 4 M were used. In addition, mice at the age of 6–7 M were included to look for any trends in gene expression that might develop during the progression of the disease. Separate RNA samples were prepared from each of three individual retinas for each age, and gene expression profiles were determined with the aid of mouse oligonucleotide arrays (Agilent). A subset of genes was examined with the aid of real-time PCR. Immunocytochemistry was used to visualize changes in the retina for some of the gene-products.

Results

Four hundred and thirteen oligonucleotide probes were differentially expressed in the retinas of 4 M versus 2 M old D2 mice. The most significantly up-regulated genes (181) were associated with immune responses including interferon signaling, the complement system and the antigen presentation pathway, whereas the down-regulated genes (232) were linked to pathways related to cell death and known neurological diseases/disorders. These particular changes were not revealed in the age-matched B6 mice. By 6 M, when IOP started to increase in many of the D2 mice, more robust changes of these same genes were observed. Changes in the levels of selected genes, representative of different functions/pathways, were validated with RT-PCR, and changes in glial responses were visualized in the retina with immunocytochemistry.

Conclusions

The results showed that the expression of genes related to the immune response and acute stress were altered independently of the development of elevated IOP, and indicated early involvement of the immune system in the onset of the disease. The later development of elevated IOP, observed in this animal model, was coincident with continued changes in expression of genes observed at earlier time points. Further studies are warranted to identify the roles of specific genes identified here with respect to the death of the RGCs.

Early Involvement of Immune/Inflammatory Response Genes in Retinal Degeneration in DBA/2J Mice

Purpose

The DBA/2J (D2) mouse carries mutations in two of its genes, Tyrp1 and Gpnmb. These alterations result in the development of an immune response in the iris, leading to iris atrophy and pigment dispersion. The development of elevated intraocular pressure (IOP) in this model of glaucoma is considered to be a significant factor leading to the death of retinal ganglion cells (RGCs). Changes in gene expression in the retina have already been correlated with the appearance of elevated IOP in the D2 mouse. The purpose of the present study was to determine if any changes in gene expression occur prior to the development of IOP.

Methods

The IOP was measured monthly using a rebound tonometer in D2 and age-matched C57/BL6 (B6) mice (normal controls). D2 animals with normal IOP at 2 and 4 M were used. In addition, mice at the age of 6–7 M were included to look for any trends in gene expression that might develop during the progression of the disease. Separate RNA samples were prepared from each of three individual retinas for each age, and gene expression profiles were determined with the aid of mouse oligonucleotide arrays (Agilent). A subset of genes was examined with the aid of real-time PCR. Immunocytochemistry was used to visualize changes in the retina for some of the gene-products.

Results

Four hundred and thirteen oligonucleotide probes were differentially expressed in the retinas of 4 M versus 2 M old D2 mice. The most significantly up-regulated genes (181) were associated with immune responses including interferon signaling, the complement system and the antigen presentation pathway, whereas the down-regulated genes (232) were linked to pathways related to cell death and known neurological diseases/disorders. These particular changes were not revealed in the age-matched B6 mice. By 6 M, when IOP started to increase in many of the D2 mice, more robust changes of these same genes were observed. Changes in the levels of selected genes, representative of different functions/pathways, were validated with RT-PCR, and changes in glial responses were visualized in the retina with immunocytochemistry.

Conclusions

The results showed that the expression of genes related to the immune response and acute stress were altered independently of the development of elevated IOP, and indicated early involvement of the immune system in the onset of the disease. The later development of elevated IOP, observed in this animal model, was coincident with continued changes in expression of genes observed at earlier time points. Further studies are warranted to identify the roles of specific genes identified here with respect to the death of the RGCs.

Response Rates to Neoadjuvant Cyclophosphamide and Doxorubicin (AC) in Breast Cancer Patients Exhibiting Her-2/Neu (Her-2) Negative, Topoisomerase II (TOPO 2A) Normal, Chromosome 17 (C17) Normal Phenotype

Background: Recent reports have suggested that Her-2, TOPO2A and polysomy 17 (C17) status may predict responsiveness of tumors to doxorubicin (DOX) therapy. These studies predominantly evaluated long term survival in the adjuvant setting. In this study we evaluate the actual response rate to neoadjuvant AC as a function of these parameters.Material and method: We identified all breast cancer patients in our registry cohort treated with neoadjuvant DOX and cyclophosphamide only prior to surgery. All had hormone receptor (HR) and Her-2 testing as part of their prior clinical evaluation. Forty patients were found, 33 of whom had sufficient tissue for testing and adequate signal for measurement of TOPO2A and C17. Fluorescence in situ hybridization (FISH) testing was done on deparaffinized tissue sections pretreated using a modification of the vendor's standard protocol, and then incubated with the FDA-approved Vysis PathVysion™ probe set, which includes Spectrum-Green-conjugated probe to the α-satellite DNA located at the centromere of chromosome 17 (17p11.1–q11.1) and a Spectrum Orange-conjugated probe to the TOP2A gene (Abbott Diagnostics, Chicago, IL, USA). Morphometric analysis was performed using a MetaSystems image analysis system, incorporating the Metafer software with extended focus/tile sampling methodology (Meta-Systems, Altlussheim, Germany). Manual counting was performed on all samples in which autofluorescence and/or artifact prevented the counting of sufficient numbers of cells. A ratio &gt; 2.0 is considered positive for TOPO2A amplification. C17 presence was defined as signal of ≥ 2.5.Results: Out of 33 patients tested, one was Topo2A amplified (HR-/Her-2-/C17-, partial responder) and one had polysomy 17 present (HR+/Her-2+/TOPO2A-, partial responder). 17 out of 33 were HR+ and eight were Her-2+. Among the TOPO2A non-amplified and C17 normal patients (n=31), treatment response was pathologically proven complete response (pCR) = 5 (16%), PR = 19 (61%), and NR = 7 (23%). Distribution by marker status and response to therapy for the 31 cases was the following: 1) HR-/Her-2- (n=9), 22% pCR, 56% PR, 22% NR; 2) HR+/Her-2- (n=15), 7% pCR, 67% PR, 27% NR; 3) HR-/Her-2+ (n=6), 33% pCR, 67% PR; 4) EstrogenR+/ProgesteroneR-/Her-2+ (n=1), NR. Among TOPO2A non-amplified and C17 normal patients the majority (77%) had significant responsiveness (CR or PR) to AC. The patients that lacked all three postulated indicators of DOX sensitivity (her-2 negative, TOPO2A normal, C17 normal) still exhibited 13% pCR (3/24) and 63% PR (15/24), with HR/Her-2 neg (triple negative) patients being more responsive than HR+ patients.Discussion: Prior predictive studies have not looked directly at response rates to doxorubicin (DOX). This data suggests that even in patients lacking all three postulated predictors there is significant response to therapy that would be difficult to attribute to cyclophosphamide alone. Patients lacking Her-2, TOPO2A and C17 should not be excluded from receiving DOX-containing regimens, either as primary therapy or as therapy for metastatic disease.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2033.

Myelodysplastic Syndrome and Acute Myeloid Leukemia Incidence Following Primary Breast Cancer Treatment

Background: Breast cancer (BC) patients receiving surgery plus radiation and/or adjuvant chemotherapy treatment are routinely monitored for incidence of myelodysplasia (MDS) and leukemia.Methods: A cohort of all breast cancer patients TNM stage 0-III treated with surgery and/or radiation or chemotherapy from 1989 to 2005 at our institution were followed for incidence of blood disorders of any type by our registry system and by linkage to the Surveillance, Epidemiology and End Results registry (SEER) for our area. Cases without surgery (n=111), with stem cell transplantation (n=98), unknown or non-standard chemotherapy regimens (n=23 + 71= 94), lost to follow up (n=66) or cancer status unknown at follow up (n=67) were excluded. The remaining 5790 cases were reviewed for incidence of leukemia including MDS and acute myelogenous leukemia (AML) post breast cancer treatment by chart review including pathology reports, SEER coding for MDS/AML, and death certificates if appropriate. Mean length of follow up was 7.17 years, range 2-18 years.Results: The mean age of MDS/AML patients was 57 years, range 33-76 years. The crude rate of MDS/AML occurrence was .29% (17/5790). 17 cases of MDS/AML (10 MDS/7 AML) occurred during the follow up period as compared with 6.22 (4.03 MDS/2.19 AML) expected on the basis of rates in the general population by age &lt;65, ≥ 65 years calculated from SEER registry data (risk ratio (observed/expected)). The risk of MDS in women &lt;65 was 11.68 times that expected and the risk of AML in women &lt;65 was 9.2 times the expected rate. Risk among women over 65 was not as large (1.38 MDS, ≥ 65, 1.21 AML, ≥ 65). Average time from treatment with radiation or chemotherapy to MDS diagnosis was 5.50 years (range 1.03-12.95) and 3.42 years (range .41-6.84) for AML. The majority of MDS/AML cases occurred in the first five years post treatment (n=10) with 7 more cases observed from 5 to 12.95 years (see figure). Initial treatment of MDS/AML patients was surgery only (n=2), surgery/chemotherapy (n=1), surgery/ radiation (n=7), and surgery/chemotherapy/radiation (n=7). The two MDS patients who had initial treatment of surgery only were subsequently treated with chemotherapy and radiation for recurrence. Fifty percent of MDS patients (5/10) received surgery and radiation treatment without adjuvant chemotherapy treatment.Discussion: The incidence of MDS/AML is very small in this cohort but significantly greater than that expected in the population at large especially among women less than 65 years of age. A significant number of women who received radiation treatment without chemotherapy developed MDS post breast cancer treatment. Average time from treatment to MDS diagnosis exceeded the 2-5 year time period previously reported as an expected interval.

Citation Information: Cancer Res 2009;69(24 Suppl):Abstract nr 2082.

A model for the toxic dose under time-varying concentration

The concept of dose-load is used widely in risk assessment literature. This concept is based on animal experiments in which the animals were exposed to constant concentration during a set period of time. However, in most accident scenarios, people are exposed to time varying concentration of the toxic materials. The extension of the dose-load concept to such conditions is not straightforward. The assumption that the dose-load is additive leads to a paradox. We suggest a different approach for extending the experimental results for time-varying concentration. We introduce the concept of the effective dose, which considers physiological recovery processes. It is found that in many cases, especially those which include intermittent time series of the concentration, the number of casualties is reduced when considering the recovery process. It is also shown that by using the effective dose concept we can resolve the apparent paradox in the dose-load concept for intermittent concentration time series. We demonstrate the importance of buildings as shelter against toxic gases especially for an instantaneous release, a fact that should be considered in hazard evaluation.

Clinical and histopathological results following TriPollar radiofrequency skin treatments

INTRODUCTION

Skin laxity, wrinkles and cellulite are common aesthetic problems associated with the aging process. These symptoms are due to the weakening and thinning of dermal connective tissue and the enlargement of hypodermal fat cells. The aim of this study was to evaluate the safety and efficacy of the TriPollar RF technology in reducing fat and collagen regeneration.

METHODS

Twelve healthy patients underwent weekly treatments on different body sites using the TriPollar technology. Treatment areas were photographed and measured and patient satisfaction was monitored. One abdominal patient consented to a series of TriPollar treatments prior to her scheduled abdominoplasty. A controlled histopathology analysis was performed on skin samples taken during the abdominoplasty procedure.

RESULTS

Histopathological examination revealed marked differences between treated and non-treated abdominal skin areas. An increase of 49% in dermal thickness, focal thickening of collagen fibers and focal shrinkage of fat cells was shown following TriPollar treatments. Average patient satisfaction indicated clear satisfaction with the clinical results achieved.

CONCLUSION

The TriPollar is a safe and effective non-invasive technology leading to skin tightening and body shaping. Histology results indicate changes at the dermal and fat layers following TriPollar treatments resulting in increased collagen regeneration and stimulated fat metabolism.

Efficacy of lenalidomide oral monotherapy in relapsed or refractory indolent non-Hodgkin's lymphoma: Final results of NHL-001

8560

Background: Lenalidomide has shown activity in a wide range of hematological malignancies. We conducted a phase II trial of single-agent lenalidomide in indolent non-Hodgkin's lymphoma (NHL). Methods: Patients with relapsed or refractory indolent NHL were eligible, with no limit on the number of previous therapies. Oral lenalidomide 25 mg was self-administered once-daily on days 1–21 of every 28-day cycle for up to 52 weeks as tolerated, or until disease progression. The primary endpoint was overall response rate (ORR), with secondary endpoints of response duration, progression-free survival (PFS), and safety. Results: Forty-three patients were enrolled and were evaluable for response and safety. Patients had received a median of 3 prior systemic therapies (1–17) and half of all patients were refractory to their last therapy. The ORR was 23% (10/43), including a complete response (CR) or unconfirmed CR (CRu) rate of 7%. The median time to first response was 3.6 months (1.7–4.2) and the median time to CR or CRu was 4.2 months (1.9–11.1). Twenty-seven percent (6/22) of patients with follicular lymphoma grade 1 or 2, and 22% (4/18) of patients with small lymphocytic lymphoma responded to therapy. The median duration of response has not reached, but is longer than 16.5 months with 7 of 10 responses ongoing at 15–28 months. Median PFS was 4.4 months (2.5–10.4). Adverse events were consistent with the known safety profile of lenalidomide and manageable; the most common grade 3 or 4 adverse events were neutropenia (30% and 16%, respectively) and thrombocytopenia (14% and 5%, respectively). Conclusions: Oral lenalidomide monotherapy produces durable responses with manageable side effects in relapsed or refractory indolent NHL and warrants further investigation in the treatment of indolent NHL.

[Table: see text]

A disorder of sympathomimetic amines leading to increased vascular permeability may be the etiologic factor in various treatment refractory health problems in women

There is an evidence that increased capillary permeability in the standing position is related to a deficit in the sympathetic nervous system. The leakage of this fluid leads to various clinical conditions which frequently puzzle the consulting physician because despite the frequency of this condition intelligent physicians and patients are unaware of the cause of their condition. One of the most common manifestations is the inability to lose weight despite proper dieting. A randomized study comparing the efficacy of a diuretic, a converting enzyme inhibitor, spironolactone and a sympathomimetic amine on weight loss in diet refractory women found that only the latter in the form of dextroamphetamine sulfate demonstrated significant weight reduction over a six month time span. In fact, the dextroamphetamine sulfate proved effective when given in the next 6 months to the three groups failing to respond for the first 6 months. The diagnosis of a deficit in sympathomimetic amines is established by demonstrating an abnormal clearance of a water load in the erect position and exclusion of other conditions that are associated with an abnormal free water clearance, e.g., hypothyroidism, renal or liver disease or congestive heart failure. The original definition of an abnormal water load test was excretion of <55% of a 1500 ml water load in 6h but we found that <75% defines a greater population who suffer from this problem. There are several conditions that have proven refractory to conventional theory that respond quickly and effectively to sympathomimetic amines. There have been many anecdotal reports of relieving interactable pain syndromes quickly and efficiently with sympathomimetic amine theory, despite failure with a multitude of other therapies. These include interstitial cystitis and pelvic pain that was attributed to endometriosis, gastrointestinal pain including esophagitis and gastroparesis, headaches, joint pain, fibromyalgia, and carpal tunnel syndrome. It is not clear if the improvement in pain is related to a decrease in fluid retention or a direct effect of the sympathomimetic amines on the sympathetic nervous system. Sympathomimetic amine theory has helped other conditions besides pain, e.g., chronic fatigue, vasomotor symptoms in young women not associated with decreased ovarian egg reserve, and chronic urticaria resistant to all other therapies. Thus, these studies strongly suggest that physicians be aware of this condition involving a deficit in the sympathetic nervous system when faced with various enigmatic complaints especially if standard therapy has not proven effective.

Seven hundred and fifty-nine (759) chances to learn: a 3-year pilot project to analyse transfusion-related near-miss events in the Republic of Ireland

BACKGROUND

The National Haemovigilance Office has collected and analysed reports on errors associated with transfusion since 2000. A 3-year pilot research project in near-miss event reporting commenced in November 2002.

MATERIALS AND METHODS

Near-miss reports from 10 hospital sites were analysed between May 2003 and May 2005. The Medical Event Reporting System for Transfusion Medicine was used to collect and analyse the data. Root cause analysis was used to identify causes of error.

RESULTS

A total of 759 near-miss events were reported. Near misses are occurring 18 times more frequently than adverse events causing harm. Sample collection was found to be the highest risk step in the work process and was the first site of error in 468 (62%) events. Of these, 13 (3%) involved samples taken from the wrong patient. Medical staff were frequently involved in error. The general wards and emergency department were identified as high-risk clinical areas, in addition, 78 (10%) events occurred within the transfusion laboratory. Three specific human and two system failures were shown to have been associated with the errors identified in this study.

CONCLUSIONS

This study confirms that near-miss events occur far more frequently than adverse events causing harm. Collecting near-miss data is an effective means of highlighting human and system failures associated with transfusion that may otherwise go unnoticed. These data can be used to identify areas where resources need to be targeted in order to prevent future harm to patients, improving the overall safety of transfusion.

Electron tomography of amplified nanogold immunolabelling: Improvement of quality based on alignment of projections with sinograms and use of post-reconstruction deconvolution

Electron tomography of immunolabelled proteins identified with amplified nanogold particles imaged by Scanning and Transmission Electron Microscopy within thick sections is a powerful method to investigate the three-dimensional organization of complex cellular machineries. In order to increase the overall quality of the reconstructed cube, we have developed two methods that improve the tomographic reconstruction process. We first performed a very precise alignment of the projections before reconstruction with a technique using sinograms. After reconstruction, we propose to compute image restoration by calculating the Point Spread Function of the projection/back-projection system and to use it to deblur the reconstructed cubes. Improvement in the quality of the reconstructed cubes is demonstrated on images of nucleolar proteins tagged with EGFP and immunolabelled with nanogold particles.

Elastolysis induces collagenolysis in a gingival lamina propria model

Elastin peptides were previously reported to increase MMP expression in several cell types. We found binding of these peptides to their receptors led to enhanced MMP-3 and MMP-1 expression, but not activation, in human gingival fibroblasts cultured on plastic dishes. We hypothesized that these peptides, in a more physiological environment, might additionally trigger an MMP-3/MMP-1 activation cascade, leading to matrix lysis, as occurs in periodontitis. To test this hypothesis, we used contracted and attached lattices as gingival lamina propria equivalents. In such 3D models, supplementation of elastin peptides and plasminogen triggered an MMP-3/MMP-1 activation cascade and significant down-regulation of TIMPs production, further leading to intense collagen degradation. We propose that elastolysis, as occurs in periodontitis, potentiates collagenolysis, thus promoting disease progression.

Snoezelen multi-sensory environments: task engagement and generalization

These experiments explored whether behavioral improvements observed during Snoezelen OT treatment sessions carried over to two different settings for three people with moderate/severe intellectual disability, autism and severe challenging behaviors. Experiment 1 explored engagement during a functional task immediately following the treatment sessions while experiment 2 explored changes in the frequencies of challenging behaviors on the days after treatment sessions. Investigators found carryover for two of the three participants to both post-session engagement as well as to the daily frequency of challenging behaviors on days following the OT sessions.

The treatment of idiopathic edema, a cause of chronic pelvic pain in women: effectively controlled chronic refractory urticaria--case reports

PURPOSE

To corroborate or refute a previous case report from 20 years ago whether treatment with sympathomimetic amines is effective in controlling chronic urticaria.

METHODS

All cases of chronic urticaria in our reproductive endocrinology and infertility practice were identified. All four had been treated with dextroamphetamine sulfate. Quickness and duration of response were then determined.

RESULTS

Four women were identified. All showed improvement within the first month. The marked improvement did not dissipate including two patients whose duration of improvement was 8.5 and 13 years, respectively.

CONCLUSIONS

Gynecologists should consider idiopathic edema as an etiology when facing chronic pelvic pain and urticaria. Since allergists and dermatologists do not seem to be aware of this treatment option, the initiation of therapy may need to come from the gynecologist.

Idiopathic orthostatic cyclic edema as a unique etiology for vasomotor flushing in a normal estrogenic woman with normal day 3 follicle stimulating hormone--case report

PURPOSE

To describe a unique cause and therapy for vasomotor flushing.

METHODS

Serum follicle stimulating hormone (FSH) and estradiol, renal and liver function studies and urinalysis were performed as well as a water load test.

RESULTS

All laboratory tests were normal but the water load test showed inadequate four-hour urine excretion when she was erect but normal when supine. Complete relief from vasomotor symptoms occurred shortly after treatment with sympathomimetic amines.

CONCLUSIONS

Idiopathic orthostatic cyclic edema can cause vasomotor flushing even with normal estrogen and serum FSH, and treatment of the edema state with the drug of choice dextroamphetamine sulfate can effectively control these symptoms.

Hydroxyethylstarch microcapsules: A preliminary study for tumor immunotherapy application

The objective of this work was to prepare microcapsules which would allow protection and slow release of antigens used for melanoma immunotherapy treatment. Hydroxyethylstarch (HES) microcapsules were prepared using interfacial cross-linking with terephthaloyl chloride (TC). They were characterized with respect to morphology (microscopy) and size (in the 4-15 microm range). Bovine serum albumin (BSA) was used as model protein for loading and release studies. Microcapsules were loaded with solutions at different protein concentrations (0.5-5%). The maximum loading efficiency (20%) was observed with the concentration of 2.5%, which allowed a loading capacity near 100%. Confocal laser scanning microscopy (CLSM) visualization showed that BSA was entrapped within the microcapsules and not only associated to their outer surface. BSA-release studies showed a 20% BSA release within 30 min while 80% remained entrapped in the microcapsules for 4 days. Microcapsules were degraded by alpha-amylase and addition of esterase to alpha-amylase enhanced slightly their degradation. In vitro studies on melanoma cells showed that HES microcapsules were non-toxic. Preliminary in vivo studies demonstrated that microcapsules were biodegradable after intraperitoneal injection (i.p.). The observation of peritoneal wash showed a complete degradation within 7 days, indicating a possible application as an in vivo drug delivery system especially to enhance the presentation of antigens.

Four-point bending strength of transverse osteotomies stabilized with various Kirschner wire and tension wire band configurations

Four different fixation configurations of K-wires of two different diameters were used to stabilize a transverse osteotomy in chicken humerus bones. Four-point bending was applied to these to assess their apex dorsal bending rigidity. The configurations of K-wires included intramedullary, crossed and two with different tension wire band designs. One of these consisted of two transverse K-wires which did not cross the fracture line, around which the tension wire band was placed. The results showed that there was no statistical significance between the two different tension band wiring techniques and that both were superior to the intramedullary and crossed K-wire fixation techniques.

[Breast reconstruction with deep inferior epigastric perforator artery free flap]

Today, breast reconstruction is an integrate part of the treatment for patients after ablative breast surgery. Many techniques of breast reconstruction were developed utilizing autologous tissues. Some of these techniques involve significant donor site morbidity, making their use questionable. We present our initial experience using the Deep Inferior Epigastric Artery (DIEA) Perforator Free Flap for breast reconstruction. The flap carries the skin and fat tissue from the abdominal wall while maintaining and preserving the abdominal wall muscles and using only it's vascular pedicle, which is re-anastomosed of the vessels on the thorax. This procedure was used in 50 women, with full success in 49 cases. There were only a few complications, most of which were treated conservatively. This technique of breast reconstruction holds many advantages: shorter recovery period, less pain, rapid return to normal activity, maintenance of the abdominal wall strength and easier insetting of the reconstructed breast with better aesthetic results.

[Sex reassignment surgery]

Israel is among the few countries in the world where sex reassignment surgery (SRS) is performed in public hospitals. Today, the only center performing SRS in Israel is the Sheba Medical Center. A multidisciplinary committee grants authorization permitting surgery after a follow-up period of two years. We found that this multidisciplinary approach leads to the best therapeutic results. We briefly present the pre-operative evaluation, operative approach, post-operative course, final results and complications of sex reassignment surgery. This article aims to inform physicians of this therapeutic option, and the indications for referral.

Hindsight bias, outcome knowledge and adaptive learning

The ubiquitous nature of hindsight bias is a cause for concern for those engaged in investigations and retrospective analysis of medical error. Hindsight does not equal foresight. Investigations that are anchored to outcome knowledge run the risk of not capturing the complexities and uncertainties facing sharp end personnel and why their actions made sense at the time. Important lessons go unlearned if the exercise is simply to back track someone else's decision landmarks. Outcome knowledge can also bias our thinking on the quality of the processes that led to the outcome. This paper examines the influence of outcome knowledge in relation to reconstructive memory and legal testimony, ways for reducing the impact of outcome knowledge, and an adaptive learning framework that places hindsight bias in a broader context of rapid updating of knowledge.

Pregnancy despite imminent ovarian failure and extremely high endogenous gonadotropins and therapeutic strategies: case report and review

PURPOSE

To attempt ovulation induction in a woman with premature ovarian failure who had very high serum follicle stimulating hormone (FSH) levels (e.g., 164 mIU/ml) by merely using ethinyl estradiol without gonadotropins.

METHODS

Ethinyl estradiol (20-40 microg) was used to lower serum FSH. Monitoring of follicular maturation was performed using sonography to determine follicle size and serum estradiol. Progesterone vaginal suppositories (200 mg twice daily) were used following demonstration of oocyte release from the follicle.

RESULTS

Follicle maturation and ovulation was achieved in six of ten treatment cycles. A clinical pregnancy occurred in the ninth treatment cycle and a live delivery of a healthy baby occurred.

CONCLUSIONS

Despite small ovaries, amenorrhea, and failure to have withdrawal menses following progesterone, absence of antral follicles on initial ultrasound, and consistently extremely high serum FSH, ovulation and pregnancy is possible by merely lowering the serum FSH.

Late-term reconstruction of lateral ankle ligaments using a split peroneus brevis tendon graft (Colville's technique) in patients with chronic lateral instability of the ankle

We reviewed 14 patients with chronic lateral instability of the ankle treated by Colville's technique between 1996 and 2001. The mean patient age was 25 (20-35) years and all were men. The mean period between injury and surgery was 25 (18-32) months, and the mean follow-up was 20 (14-32) months. Twelve of the results were excellent and two were good according to the criteria of Chrisman and Snook. All patients returned to normal daily activity levels at an average of 6 months following surgery.

A case for associative peer to peer overlays

The success of a P2P file-sharing network highly depends on the scalability and versatility of its search mechanism. Two particularly desirable search features are scope (ability to find infrequent items) and support for partial-match queries (queries that contain typos or include a subset of keywords). While centralized-index architectures (such as Napster) can support both these features, existing decentralized architectures seem to support at most one: prevailing protocols (such as Gnutella and FastTrack) support partial-match queries, but since search is unrelated to the query, they have limited scope. Distributed Hash Tables (such as CAN and CHORD) constitute another class of P2P architectures promoted by the research community. DHTs couple index location with the item's hash value and are able to provide scope but can not effectively support partial-match queries; another hurdle in DHT deployment is their tight control the overlay structure and data placement which makes them more sensitive to failures.Associative overlays are a new class of decentralized P2P architectures. They are designed as a collection of unstructured P2P networks (based on popular architectures such as gnutella or FastTrack), and the design retains many of their appealing properties including support for partial match queries, and relative resilience to peer failures. Yet, the search process is orders of magnitude more effective in locating rare items. Our design exploits associations inherent in human selections to steer the search process to peers that are more likely to have an answer to the query.

Nosocomial hepatitis C virus infection in a renal transplantation center

Nosocomial hepatitis C virus (HCV) infections were recorded in the renal transplantation unit of the university hospital. There were cases of acute HCV infection with aggressive clinical courses diagnosed from a positive HCV RNA test in the early post-transplantation period and which remained anti-HCV negative. Their anti-HCV seronegativity was attributed to them having acquired HCV under intense immunosuppressive therapy and suggested that the aggressive clinical course could be due to the deficient immune response resulting in an inability to limit viral replication. There were also donors diagnosed as having acute HCV infection in the early post-operative period. Genotyping and sequence analysis for HCV were performed on the isolates of eight of these patients who were consecutively transplanted and of three donors whose recipients were infected with HCV prior to transplantation, and who acquired acute HCV infection after transplantation. Of the eight recipients in the first group three were genotype 1a, three were genotype 1b, one was genotype 3a, and the last one was genotype 4 according to Simmond's classification. Of the three donor-recipient couples both the HCV isolates from one couple were genotyped as 1b and the phylogenetic analysis indicated that the patients were infected with a common variant of HCV, but the genotypes of HCV isolates from the other couples were different. Recipients were genotype 1b and the donors were genotype 1a in these couples. Genotype results of the first group and donor-recipient couples, and sequence analysis of genotype 1b and 1a isolates, showed that the source of infection was not a unique strain and there were multiple breaks in universal precautions while managing these patients.

Effects of stem design and pre-cooling prostheses on the heat generated by bone cement in an in vitro model

The necrotizing effects of the heat, particularly at more than 50 degrees C, produced by the exothermic polymerization process associated with the acrylic implant cement polymethylmethacrylate (PMMA) are well documented. The temperature changes that occur are dependent on the thickness of the PMMA. The current study investigates the hypothesis that the heat produced by the bone cement may be reduced by the choice of stem design and by pre-cooling the hip prosthesis. The thermal alterations at the bone-cement interface were measured in an in vitro model. The results indicated that a temperature decrease of approximately 7 degrees C could be achieved by pre-cooling the prosthesis, and by changing the shape of the prosthesis stem from flat and wide to round.

Treatment of rhinophyma with Er:YAG laser

BACKGROUND AND OBJECTIVE

Rhinophyma is a benign, disfiguring disorder of the nose which presents the end stage of acne rosacea, and can also occasionally result in nasal airway obstruction. We describe the first series of patients treated with Erbium laser.

STUDY DESIGN/MATERIALS AND METHODS

Severe-to-moderate rhinophyma in six patients were treated at our institution between 1995 and 1996, using the Erbium:YAG (Erb:YAG) laser.

RESULTS

All patients achieved marked cosmetic improvement, with no complications. Post-operative healing time was seven to fourteen days-significantly shorter than similar other modalities.

CONCLUSIONS

The Erbium laser provides very accurate tissue ablation and allows the sculpturing of the hypertrophied areas, offering good cosmetic results, with a very short healing period as shown in our study.

Improved peptide detection with matrix-assisted laser desorption/ionization mass spectrometry by trimethylation of amino groups

Trimethyl alpha-amino derivatives of peptides (penta to deca) with a permanent positive charge on their alpha-amino groups were prepared by in vacuo reaction with iodomethane and subjected to matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). Compared to the unmodified peptide, the signal intensity of the trimethyl alpha-amino derivative in MALDI-MS is increased by at least an order of magnitude. Similarly, an octapeptide with a trimethylated epsilon-amino group derived from the solitary lysine residue of the B-chain of insulin also shows the same relative increase in signal intensity. Another advantage of the in vacuo methylation procedure is that trimethylation of a peptide amino group can be carried out readily with a combination of isotopes (13)CH(3)I and (12)CH(3)I or CD(3)I and CH(3)I, yielding a doublet signal either 3 or 9 units apart, respectively. The presence or absence of such a doublet signal can be used as a criterion to discriminate between peptide and non-peptide signals in the mass spectrum.

Aging through cascaded caches

The Web is a distributed system, where data is stored and disseminated from both origin servers and caches . Origin servers provide the most up-to-date copy whereas caches store and serve copies that had been cached for a while. Origin servers do not maintain per-client state, and weak-consistency of cached copies is maintained by the origin server attaching to each copy an expiration time. Typically, the lifetime-duration of an object is fixed, and as a result, a copy fetched directly from its origin server has maximum time-to-live (TTL) whereas a copy obtained through a cache has a shorter TTL since its age (elapsed time since fetched from the origin) is deducted from its lifetime duration. Thus, a cache that is served from a cache would incur a higher miss-rate than a cache served from origin servers. Similarly, a high-level cache would receive more requests from the same client population than an origin server would have received. As Web caches are often served from other caches (e.g., proxy and reverse-proxy caches), age emerges as a performance factor. Guided by a formal model and analysis, we use different inter-request time distributions and trace-based simulations to explore the effect of age for different cache settings and configurations. We also evaluate the effectiveness of frequent pre-term refreshes by higher-level caches as a means to decrease client misses. Beyond Web content distribution, our conclusions generally apply to systems of caches deploying expiration-based consistency.

In vacuo esterification of carboxyl groups in lyophilized proteins

A new method is described for the esterification of carboxyl groups in proteins by reaction of the lyophilized protein in vacuo with gaseous alcohol and HCI catalyst. Carboxyl groups are rapidly esterified with no protein degradation. 13C-Methyl or 13C-ethyl esters of the alpha-, gamma- and delta-carboxyl groups could be distinguished by the distinct chemical shifts of their resonances. Within the class of gamma- or delta-esters, the chemical shifts have little variation; however, the chemical shift of a C-terminal esterified alpha-carboxyl group shows a strong dependence on the nature of the C-terminal amino acid and sequence. Iodomethane reacts with deprotonated carboxyl groups in lyophilized proteins to form methyl esters, but unlike the reaction with gaseous methanol/HCI, it does not selectively methylate carboxyl groups. The procedure permits the cost-effective incorporation of isotopic labels and provides a new approach using 13C-NMR spectroscopy for determining the number of different C-termini present in a protein preparation.